Fish Oil and Heart Health

DURHAM, NORTH CAROLINA. Ventricular ectopy (premature ventricular complexes or PVCs) affects many heart attack victims, but is also a problem for atrial fibrillation patients. Ventricular ectopy, if sustained, can lead to ventricular fibrillation in patients with heart disease and ventricular fibrillation, in turn, can result in sudden cardiac death (SCD). There is substantial evidence that EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the main components of fish oil, protect against the development of coronary heart disease (CHD) and help prevent SCD in patients who have suffered a heart attack (myocardial infarction or MI). There is also evidence that the plant-based omega-3 fatty acid alpha-linolenic acid (ALA) may be cardioprotective. Researchers at Duke University now report that omega-3 fatty acids may be helpful in reducing ventricular ectopy in recovering MI patients.

Their study involved 260 MI patients who were enrolled in the study within 72 hours of their heart attack. Most of the study participants were male (62.9%) with an age ranging between 27 and 86 years, and an average left ventricular ejection fraction of 52%. Most of the patients (88.5%) were taking beta-blockers at the time of their assessment and, not surprisingly, most had one or more comorbid conditions. Thus, 59% had hypertension, 41% diabetes, 12% chronic obstructive pulmonary disorder (COPD), and 7% congestive heart failure. Seventy-three percent had a history of smoking and 57% were current smokers.

All participants completed the Harvard food-frequency questionnaire to determine their average dietary intake of omega-3 fatty acids during the year preceding their MI. They also underwent 24-hour Holter monitoring either during or immediately following their hospital stay. Evaluation of the data collected showed a clear inverse relationship between the intake of omega-3 fatty acids and the number of daily PVCs (including couplets, triplets, bigeminy, etc). Based on a daily energy intake of 1000 kcal, the researchers observed that an average daily intake of 0.6 gram of n-3 fatty acids was associated with 450 PVCs/day, while an intake of 0.9 gram/day was associated with only 235 PVCs/day. They estimate that a 1-gram/day increase in the intake of EPA + DHA could reduce the number of PVCs by as much as 800/day. ALA reduced PVCs in a similar fashion, but although it has been shown to help prevent CHD, there is no evidence that it reduces SCD. The researchers conclude that future randomized, controlled trials are needed to investigate whether fish oil supplementation during hospitalization for MI will reduce the number of sudden cardiac deaths.
Smith, PJ, et al. Association between n-3 fatty acid consumption and ventricular ectopy after myocardial infarction. American Journal of Clinical Nutrition, Vol. 89, May 2009, pp. 1315-20

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